1. Field of the Invention
The present invention relates to way systems for band sawing machines of the moving head variety and more particular to direct coupled way systems for obviating dimensional changes in the distance between the downstream support member and the downstream section of the movable head due to deflecting in the movable head and other structural components caused by fluctuations in the cutting force thereby avoiding unwanted vibrations.
2. Description of the Prior Art
Band saw machines of the movable head variety can be grouped into essentially three categories or types. The first, and perhaps the most common, type is that commonly referred to as the scissors type cutoff saw wherein the head portion of the band saw machine is pivotally raised and lowered relative to the work area in a scissors motion. During the downstroke the controlled pivotal or scissors closing movement of the cutting stretch of the cutting band cuts through the work piece. The second type moving head band saw machine, which may be referred to as a vertical feed band saw machine, employs one or two posts, usually oriented in the vertical direction, which guide the head of the band saw machine as it is vertically raised and lowered with respect to the work area. The head portion of the second type band saw machine customarily remains horizontal at all times during operation and cutting of the work piece occurs during the controlled downward movement of the head. The third general type of movable head band saw machine is commonly referred to as a tilt frame or tilt head band saw machine. In the tilt head band saw machine, the head portion of the saw generally carries or supports two band wheels and is mounted approximately mid-way between the wheels to a slidably mounted support member which may be referred to as a movable carriage. The movable carriage in turn, is supported on the band saw machine base through a carriage way system which permits a translatory motion of the carriage and movable head relative to the work area, such translatory motion usually being in the horizontal plane. In the tilt frame band saw machine, a work table or work surface is supported by the band saw machine base above or higher than the movable carriage and carriage way such that the movable carriage supporting the movable head is permitted to move toward and away from the front of the band saw machine with the cutting stretch of the cutting band being fed through the work area for cutting a work piece. The movable head of a band saw machine of this third type is customarily mounted to the movable carriage by means of a pivotal connection which permits the entire movable head to be tilted out of the vertical plane for purposes of making an angular cut through the work piece as the movable carriage supporting the movable head is slideably moved toward the front of the machine.
In movable head band saw machines of the first, second and third types, the cutting edge of the cutting band is customarily twisted by means of blade guides to face the work area and is pulled crosswise through the work piece by a linear force, commonly referred to as a cutting force, which is imparted to the cutting band by the downstream band wheel, i.e. the band wheel receiving the cutting band immediately after it has passed through the work piece, even through the band saw machine may be driven by the upstream band wheel. Due to inconsistencies in the teeth of the cutting band or band saw blade, variations and inconsistencies in the work piece material, and the chip production action of the cutting band teeth, the cutting force fluctuates substantially and quite rapidly during cutting operations. Of course, in a reactionary sense, the cutting band of the band saw machine imparts on the downstream band wheel a force which is equal and opposite to the cutting force. Thus, the rapid fluctuations in the cutting force give rise to rapid fluctuations in the equal and opposite force acting on the downstream band wheel and directed toward the work piece and, thus, tending to cause deflections in the frame of the movable head and other structural members. Such deflections result in dimensional changes in the distance between the downstream support member, i.e. the support member between the work piece and the downstream band wheel, and the downstream portion of the movable head thereby causing vibrations in the movable head and other band saw machine structural members connected to the movable head. Because of the indirect path which counteracting forces tending to avoid such deflections must take through a series of adjoining structural components between the work piece and the downstream band wheel, these deflections of the movable head and other band saw machine structural members continue to cause unwanted vibrations in the band saw machine during cutting operations. In the absence of such deflections, rapid fluctuations in the cutting force would be reflected as rapidly fluctuating tensile stresses in the cutting band and would be countered by increased drive power from the band saw machine drive wheel. Rapid fluctuations in the equal and opposite reaction force acting upward on the downstream wheel could be absorbed as tensile stresses or compressive forces by other structural components. However, no effective means has thus far been devised for avoiding such deflections in movable head type band saw machines.
Thus, it would be a desirable advance in the art to provide a way system for directly coupling the downstream support member and the downstream portion of the movable head in band saw machines to avoid deflections in the movable head and other structural component and dimensional changes in the distance between the downstream support member and the downstream portion of the movable head thereby avoiding unwanted vibrations resulting from rapid fluctuations in the cutting force. It would be a further advance in the art to provide a direct coupled way system for band saw machines which can be varied for use in connection with any one of the three general types of band saw machines to eliminate deflections in the movable head and other structural components caused by rapid fluctuations in the cutting force. It would be yet another desirable advance in the art to eliminate movable head and other structural component vibrations by providing a direct coupled way system comprising a shoe means and a leg means which may be integrally molded or otherwise rigidly connected in band saw machines wherein the movable head is constrained to one degree of motion relative to the work piece and may be slidably connected in band saw machines wherein the movable head is permitted more than one degree of motion relative to the work piece.